Adjustable guide vane with convexly shaped, radially inner storage section for a gas turbine, in particular an aircraft gas turbine

ABSTRACT

An adjustable guide vane for a compressor, in particular a high-pressure compressor, of a gas turbine, in particular an aircraft gas turbine is described, said vane comprising a radially outer storage section, a radially inner storage section, and a vane section, which extends in the radial direction between the outer storage section and the inner storage section, wherein the outer and the inner storage sections are designed in such a way that the adjustable guide vane can be taken up rotatably about a vane axis in the compressor, and wherein the radially inner storage section is designed like a journal (cone-shaped) and has a casing surface that revolves relative to the vane axis, said surface being of convex shape. In this way, it is provided that the radius of curvature of the convex casing surface is at least double the maximum diameter of the storage section.

BACKGROUND OF THE INVENTION

The present invention relates to an adjustable guide vane for acompressor, in particular a high-pressure compressor, of a gas turbine,in particular an aircraft gas turbine, said vane comprising a radiallyouter storage or bearing section, a radially inner storage section, anda vane section, which extends in the radial direction between the outerstorage section and the inner storage section, wherein the outer and theinner storage sections are designed in such a way that the adjustableguide vane can be taken up in the compressor so that it is rotatableabout a vane axis, and wherein the radially inner storage section isdesigned like a journal (cone-shaped) and has a casing surface thatrevolves relative to the vane axis, said surface being of convex shape.Further, the invention relates to a gas turbine having a compressor anda plurality of adjustable guide vanes of this kind.

Directional indications such as “axial” or “axially”, “radial” or“radially”, and “peripheral” are basically to be understood as referredto the machine axis of the gas turbine, as long as a different meaningdoes not ensue explicitly or implicitly from the context.

Adjustable guide vanes with ball-shaped inner storage sections areknown, for example, from DE 10 2019 122 851 A1 and EP 2 817 490 B1.

For bearing adjustable guide vanes in compressors of gas turbines, bothradially outer as well as radially inner, cylindrical sleeve bearings,particularly in the form of cylindrical drill holes are used as therespective receivers for the storage or bearing sections of theadjustable guide vanes. Additionally, bushings or sleeves can be used asparts subject to wear, wherein such bushings or sleeves are arranged inthe path of force transfer between the respective storage section of theadjustable guide vane and the respective cylindrical sleeve bearing.

It has been shown both for ball-shaped inner storage sections and forcylindrical inner bearing sections that the force transfer in the regionof the inner storage section can lead to sharply increased point loadsor surface loads in the sleeve bearing. In particular, surface loads onthe sleeve bearings and the cylindrical storage sections lead tounwanted wear.

SUMMARY OF THE INVENTION

The object that is the basis for the invention is to propose anadjustable guide vane with which the above disadvantages can be reducedor prevented.

In order to achieve this object, an adjustable guide vane and a gasturbine with the features of the present invention are proposed.Advantageous embodiments with appropriate enhancements are discussed indetail below.

Thus, an adjustable guide vane for a compressor, in particular for ahigh-pressure compressor, of a gas turbine, in particular an aircraftgas turbine, is proposed, said vane having a radially outer storagesection, a radially inner storage section, and a vane section, whichextends in the radial direction between the outer storage section andthe inner storage section, wherein the outer and the inner storagesections are designed in such a way that the adjustable guide vane canbe taken up in the compressor so that it is rotatable about a vane axis,and wherein the radially inner storage section is designed like ajournal (cone-shaped) and has a casing surface that revolves relative tothe vane axis, said surface being of convex shape. In this way, it isprovided that the radius of curvature of the convex casing surface is atleast double the maximum diameter of the storage section.

By way of such a configuration of the casing surface, the radially innerstorage section has a shaping that makes possible an improved forcetransfer between the storage section and the sleeve bearing,particularly in the operation of the compressor during correspondingforce effects. In this case, the radius of curvature of the casingsurface is selected high enough that, on the one hand, there is nocomplete surface contact between casing surface and sleeve bearing, and,on the other hand, there is also no point contact as would be the casefor a ball-shaped configuration. The curved casing surface with largeradius makes possible a partial surface contact between the casingsurface and the sleeve bearing, in particular during operation and undercorresponding force effect, so that the surface load in this region canbe optimally distributed.

In the case of the adjustable guide vane, the radius of curvature of theconvex casing surface can be from three times to ten times the maximumdiameter of the storage section. It is possible thereby to form amatching convex curvature of the casing surface.

Further, in the case of the adjustable guide vane, the convex casingsurface can be formed by a plurality of casing surface sections, eachhaving a different radius of curvature. It is thus conceivable that theconvex casing surface is formed by a plurality of different radii ofcurvature that transition into one another, so to speak. For example, itis conceivable that the radius of curvature in a central or middleregion is greater than in regions of the inner storage section or thecasing surface that lie radially further inside or outside.

Further, a gas turbine, in particular an aircraft gas turbine isproposed that has at least one adjustable compressor, particularly anadjustable high-pressure compressor, wherein it is provided that thecompressor has a plurality of the above-described adjustable guide vanesthat are arranged next to one another in the peripheral direction.

In the case of the gas turbine, the compressor can have a radially innerbearing ring having a plurality of cylindrical drill holes that arearranged next to one another in the peripheral direction, wherein aninner storage section with convex casing surface is taken up in eachcylindrical drill hole.

Further, the gas turbine can have a radially outer adjustable ringdevice that is joined with the radially outer storage sections of theadjustable guide vanes in such a way that all adjustable guide vanes aresimultaneously rotatable about their respective vane axis.

It can also be stated relative to the dimensioning of the cylindricaldrill hole in the inner bearing ring and the radius of curvature of thecasing surface of the inner storage section of the adjustable guide vanethat the radius of curvature of the casing surface is at least doublethe diameter of the cylindrical drill hole, and in particular is threeto ten times as much.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURES

The invention will be described below with reference to the appendedfigures by way of example and not in any limiting manner.

FIG. 1 shows in a simplified schematic illustration a diagram of anaircraft gas turbine.

FIG. 2 shows in a simplified and schematic sectional illustration anadjustable guide vane with its radially inner storage section.

DESCRIPTION OF THE INVENTION

Schematically and simplified, FIG. 1 shows an aircraft gas turbine 10,which is illustrated as a turbofan engine purely by way of example. Thegas turbine 10 comprises a fan 12, which is surrounded by a casing 14,which is simply indicated. In the axial direction AR of the gas turbine10, a compressor 16 is connected to the fan 12, the compressor beingtaken up in a simply indicated inner housing 18 and can be designed as asingle-stage or a multistage compressor. The combustion chamber 20 isconnected to the compressor 16. Hot exhaust gas streaming out from thecombustion chamber then flows through the subsequently connected turbine22, which can be designed as a single-stage or a multistage turbine. Inthe present example, the turbine 22 comprises a high-pressure turbine 24and a low-pressure turbine 26. A hollow shaft 28 connects thehigh-pressure turbine 24 to the compressor 16, in particular ahigh-pressure compressor 29, so that these are driven or rotatedjointly. In the radial direction RR of the turbine, another inner-lyingshaft 30 connects the low-pressure turbine 26 to the fan 12 and to alow-pressure compressor 32, so that these are driven or rotated jointly.A thruster 33, which is only indicated here, is connected to the turbine22.

In the illustrated example of an aircraft gas turbine 10, a turbinemidframe 34 is arranged between the high-pressure turbine 24 and thelow-pressure turbine 26, and is arranged also around the shafts 28, 30.In its radially outer region 36, hot exhaust gases from thehigh-pressure turbine 24 flow through said turbine midframe 34. The hotexhaust gas then reaches an annular space 38 of the low-pressure turbine26. By way of example, rotating blade cascades 27 are illustrated fromcompressors 29, 32 and turbines 24, 26. Guide vane cascades 31 that areusually present are illustrated only in the compressor 32 by way ofexample, for reasons of clarity.

The description below of an embodiment of an adjustable guide vaneparticularly refers to the compressor 16, in particular thehigh-pressure compressor 29.

In a simplified and schematic sectional illustration, FIG. 2 shows anadjustable guide vane 50. The adjustable guide vane 50 comprises aradially inner storage section 52. Radially toward the outside, a vanesection connects to the storage section 52. The vane section in thiscase extends radially outside up to a radially outer storage section 56,which is indicated here only very simply.

The outer and inner storage sections 52, 56 are thus embodied here insuch a way that the adjustable guide vane 50 is rotatable about a vaneaxis SA in the compressor. The radially inner storage section 52 isdesigned like a journal (cone-shaped) and has a casing surface 58 thatrevolves relative to the vane axis SA, said surface being of convexshape. In this case, the radius of curvature KR of the convex casingsurface 58 is at least double the maximum diameter DM of the storagesection 52.

In FIG. 2 , two radii of curvature KR of the casing surface 58 areindicated by dot-dash lines that do not intersect in FIG. 2 (on theright). In this way, it can be seen that a central point for a circle,whose radius corresponds to the radius of curvature KR, is found outsideFIG. 2 , and that the radius of curvature KR is clearly greater than thediameter DM of the storage section 52.

The selected diagram illustrates also that the radius of curvature KR ofthe convex casing surface 58 can be three to ten times the maximumdiameter DM of the storage section 52.

Although this is not explicitly shown in FIG. 2 , the convex casingsurface 58 can also be formed by a plurality of casing surface sections,each of which has a different radius of curvature. In this case, each ofthe different radii of curvature fulfill the above-mentioned conditionsin relation to the diameter DM of the storage section 52.

In an aircraft gas turbine 10, which is shown in FIG. 1 and which has atleast one adjustable compressor, in particular the adjustablehigh-pressure compressor 29, the compressor 29 can have a plurality ofadjustable guide vanes that are arranged next to one another in theperipheral direction, as they have been described above with referenceto FIG. 2 . For this, the compressor 29 can have a radially innerbearing ring 60 (FIG. 2 ) with a plurality of cylindrical drill holes 62that are arranged next to one another in the peripheral direction,whereby an inner storage section 52 with convex casing surface 58 isreceived in each cylindrical drill hole 62. The diameter of a drill hole62 in this case essentially corresponds to the maximum diameter DM ofthe storage section 52, so that, also with respect to the diameter ofthe drill hole, it is valid that the radius of curvature KR of thecasing surface 58 is at least twice as large as the diameter of thedrill hole 62.

What is claimed is:
 1. An adjustable guide vane for a high-pressurecompressor of an aircraft gas turbine, comprising: a radially outerstorage section, a radially inner storage section, a vane section, whichextends in the radial direction between the outer storage section andthe inner storage section, wherein the outer and the inner storagesections are configured and arranged so the adjustable guide vane can betaken up rotatably about a vane axis in the compressor, and wherein theradially inner storage section is configured and arranged as acone-shaped journal or a plate and has a casing surface that revolvesrelative to the vane axis, the surface being of convex shape, wherein aradius of curvature of the convex casing surface is at least double themaximum diameter of the radially inner storage section.
 2. Theadjustable guide vane according to claim 1, wherein the radius ofcurvature of the convex casing surface is three to ten times the maximumdiameter of the storage section.
 3. The adjustable guide vane accordingto claim 1, wherein the convex casing surface is formed by a pluralityof casing surface sections, each having a different radius of curvature.4. The adjustable guide vane according to claim 1, wherein theadjustable guide vane is mounted exclusively over the storage section onits radially inner-lying side relative to the vane section.
 5. Anaircraft gas turbine, comprising: at least one adjustable high-pressurecompressor, wherein the high-pressure compressor has a plurality ofadjustable guide vanes arranged next to one another in the peripheraldirection according to claim
 1. 6. The aircraft gas turbine according toclaim 5, wherein the compressor has a radially inner bearing ring with aplurality of cylindrical drill holes that are arranged next to oneanother in the peripheral direction, wherein an inner storage sectionwith convex casing surface is taken up in each cylindrical drill hole.7. The aircraft gas turbine according to claim 5, wherein it has aradially outer adjustable ring device that is joined with the radiallyouter storage sections of the adjustable guide vanes so that alladjustable guide vanes are simultaneously rotatable about theirrespective vane axis.